Primary alkaline cell



Dec. 10, 1957 P. s. KORT PRIMARY ALKALINE CELL' Filed April 2e. 1 956wf@ w a ffy:

1 l; ANairn 2,816,153 rnnvrAnY ALKALINE CELL Paul G. Kort, Freeport,Ill., assigner to Burgess Battery Company, Freeport, lll., a corporationof Delaware Application April 26, 1956, Serial No. 580,857

Claims. (Cl. 136--107) This invention relates to primary electric cellsand particularly to structure for current-producing dry cells having analkaline electrolyte.

` In dry cells of the type mentioned, gas is generated 1n the cell whileit stands on open circuit and unless such gas is vented in a propermanner, pressure is built up within the cell until rupture of theenclosure occurs or the seal of the cell is forced open and the gasescapes and carries with it some of the liquid cell electrolyte. Leakageof electrolyte is objectionable, in that it has a deleterious effectupon objects with which it comes in Contact, as is well known.

It is the object of the present invention to provide a dry cell of thecharacter described having a structure which serves to vent the gases tothe surrounding space and at the same time inhibits leakage of liquidelectrolyte to the exterior of the cell.

Other objects of the invention will become apparent from the followingdescription, which is to be read in conjunction with the accompanyingdrawing in which Fig. l is a vertical sectional view of an embodiment ofa cell constructed in accordance with the invention,

Fig. 2 is atop view of said embodiment, and

Fig. 3 is a fragmental sectional View of a different embodiment of theinvention.

In the cell embodiment illustrated in Figs. l and 2, there are twoopen-top cups and 20 arranged in mutually telescoping relation to formthe enclosure for the cell. The inner cup 10 is composed of a suitablemetal such as steel and has its open-top directed downwardly and has themajor central portion of its bottom dished upwardly as shown to form thedished portion 12. Between the dished portion 12 and the cylindricalwall of inner cup 10 is the annular shoulder 14. The exterior surface ofsteel cup 1G may be nickel-plated if desired. The interior surface ofthe dished portion 12 has an adherent coating 16 of zinc thereon, formedby plating or other suitable method. Within said dished portion 12 andresting in contact with zinc layer 16 is the negative electrode or anode18 of the cell, said anode being composed of amalgamated zinc andpreferably being in the form of a body of compressed amalgamated zincparticles. The amalgamated zinc powder is pressed into the dishedportion 12 under such pressure that it remains rrnly in place throughoutthe life of the cell.

The outer cup 20 is composed of a suitable metal such as steel and hasits open top directed upwardly. The exterior surface of steel cup 20 maybe nickel-plated if desired. Between the cylindrical edge of the opentop of inner cup 1t) and the bottom wall of outer cup 20 is an annularsealing gasket 22 of a suitable compliant sealing material such ascompliant neoprene, polyethylene, or polyvinyl chloride. Such gasket 22is shaped in cross section in the form of a deep, narrow U, the base ofthe U being under pressure between the edge of the inner cup lil and thebottom of the outer cup 20, the outer leg of the U extending upwardly ashort distance in Contact arent Patented Dec. 1o, 1957 with the exteriorsurface of cup 10 within the space between said cup and outer cup 20,and the innerleg extending upwardly a greater distance, somewhat morethan one-half of the height of cup 10, in contact with the interiorsurface of said cup 10.

The upper end portion of the cylindrical wall of outer cup 20 is turnedinwardly to form the flange 24 and an annular spacing member 26 isarranged between shouldery 14 and flange 24. Spacing member 26 iscomposed of a suitable substantially rigid non-conductive material suchas rigid neoprene, modified polystyrene, or vulcanized fiber. Thearrangement is such that spacing member 26 is clamped between ange 24and shoulder 14 under pressure as will be described more fullyhereinafter. Such pressure is transmitted to gasket 22. Spacing member26 maintains the cylindrical walls of the inner and outer cups spacedapart to provide the annular space 28 within which is the mass ofabsorbent material 30 which may be absorbent paper such as blottingpaper. Within outer cup 20 and fixed to the bottom wall of the latter asby welding or soldering is a third open top cup 34 which is alsocomposed of steel. The exterior diameter of cup 34 is less than theinterior diameter of cup 1t) to leave a narrow annular space between thetwo members. Cup 34 is shallow in relation to the height of cups 10 and2) to leave a substantial space between the top of said cup 34 and thesurface of anode 18.

Within cup 34 is the depolarizing cathode 36 which Vis composed of amixture of powdered suitable oxygen-yielding substance such as mercuricoxide, mercurous oxide, silver oxide, silver peroxide, cupric oxide,cuprous oxide, or other readily-reducible oxygen-yielding compound, ormixtures of such compounds, and a suitable conductive substance such asmicronized graphite. The depolarizer composition is compressed into cup24, the amount of composition being sufiicient to fill cup 24substantially level with the top edge thereof.

Resting upon the top surface of the depolarizing cathode 36 and theupper edge of cathode cup 34 is a relatively thin barrier disk 38 of asuitable liquid and ionpermeable material, resistant to the action ofthe electrolyte, such as parchment paper, vinyl resin, vinylidine resin,or the like, The edge of said disk 38 extends outwardly beyond the sideWall of cup 34 and into Contact with gasket 22. Above the barrier disk3S is the electrolyte-receptive body 4l) which is composed of a suitableporous, absorbent, electrolyte-resistant material, such as wood bers,cotton fibers, or the like, examples of which are porous absorbent paperand cotton. rlhe body 40 is of cylindrical shape and has a diametersmaller than the internal diameter of inner cup iti whereby an annularspace is provided between the cup 10 and the body 4t). The body 40 isunder compression between the anode 18 and the barrier disk 38 and issufficiently porous to be highly absorbent of the liquid electrolyte ofthe cell.

The electrolyte of the cell is contained in absorbed condition in theabsorbent body 40. The electrolyte is an aqueous solution of a suitablealkaline substance, such as potassium hydroxide, sodium hydroxide,lithium hydroxide, and mixtures of such hydroxides.

The barrier disk 38 is minutely porous and is permeable to the liquid ofthe electrolyte and to the substances which are in solution therein,that is, the barrier 38 is liquidand ion-permeable. At the same time,said barrier is impervious to solid particles. The electrolyte and theions thereof freely traverse said barrier but particles are preventedfrom migrating from the depolarizer 36.

animes 3. for holding the electrolyte in a substantially immobilizedcondition.

As stated heretofore, gas is usually generated in the cell while,standing .on open circuit. If gas .pressure within inner cup 10 ismoderate, gasket 22,forms a seal between inner cup 10 and outer cup 20,and the gas is retained within cup 10. If excessive gas pressure isdeveloped in cup 10, gas forces its way past gasket 22 and into theannular space 28 from which it is vented to the atmosphere by escapingpast spacing member 26. lf gas escaping past gasket 22 is accompanied bycell liquid, such liquid is absorbed and retained by the body ofabsorbent material 30. This result is accomplished by reason of the factthat gasket 22 is composed of a compliant material and spacing member 26is composed of a substantially rigid material, as has been described.Gasket 22, because of its compliance, forms an eiective seal whichpermits the escape of gas only when the latter is under high pressure.When the gas escapes under high pressure, there is a tendency for it tocarry the cell liquid with it. Because spacing member 26 issubstantially rigid, and the cooperating surfaces of said spacing memberand cups 10 and 20 are not perfectly smooth, member 26 does not form aseal but permits the ready escape of gas under low pressure. When thegas escapes under low pressure past spacing member 26, there issubstantially no tendency for it to carry liquid with it, for the cellliquid is effectively absorbed by the porous material 30. Thus, there isno objectionable leakage of liquid from the cell.

As an alternative structure, as illustrated in Fig. 3, spacing member 26may be composed of a compliant material similar to that of which gasket22 is composed. In such case, member 26 is also a sealing member andprevents escape of gas except when the latter is under high pressure.With such a sealing member 26, a vent opening 40 is provided in thecylindrical Wall of outer cup 2t) between sealing member 26 andabsorbent member 3b. Gas escaping past gasket Z2 is vented to theatmosphere through opening 40, and liquid carried by the gas is absorbedabsorbent member 30, and leakage of liquid to the exterior of the cellis inhibited.

What is claimed is:

l. An electric cell comprising a pair of open top metal cups oppositelyoriented and in mutually telescoping relation, the side Walls of saidcups being spaced apart to form an annular space therebetween, a gasketunder pressure between the edge of the inner cup and the bottom of theouter cup, said gasket being generally U-shaped in cross section andextending in contact with the interior and exterior surfaces of the sidewall of said inner cup, said gasket permitting escape of gas underpressure from the interior of said' inner cup, the bottom portion ofsaid inner cup providing an annular shoulder, an inturned flange on saidouter cup overlying said shoulder,

a spacing member between said ilanges and said shoulder, aliquid-absorbent member within said annular space, means for venting gasfrom said annular space located beyond said liquid-absorbent member withrespect to said' gasket, a third open top cup within said outer cup, atirst electrode arranged in said inner cup and a` second electrodearranged in said third cup,l the bottoms of'said thirdand outer cupsbeing joined together, said third cup being shallow relative to saidinner and outer cups to provide a space between said electrodes, aliquid-absorbent body between said electrodes, and electrolyteimpregnating said absorbent body.

2. An electric -cell comprising a pair of open-top metal cups oppositelyoriented and in mutually telescoping relation, the side walls of saidcups being spaced apart to forman annular space therebetween, a gasketunder pressure between the edge of the inner cup and the bottom of theouter cup, said gasket being generally U-shaped in cross section andextending incontact with`- the interior and exterior surfaces of theside wall" of said' inner cup,

said gasket permitting escape of gas under pressure from the interior'of said inner cup, the bottom portion of said inner cup providing anannular shoulder, an inturned flange on said outer cup overlying saidshoulder, a spacing member between said ange and said shoulder, aliquid-absorbent member within said annular space, means for venting gasfrom said annular space located beyond said liquid-absorbent member withrespect to said gasket, a third open top -cup within said outer cup, an`anode arranged in said inner cup and a cathode arranged in said thirdc-up, the bottoms of said third and outer cups being joined together,the surface of said cathode being substantially ush with the edge of therim of said -third cup, said third cup being shallow relative to saidinner and outer cups to provide a space between said anode and saidcathode, a liquid-absorbent body between said anode and said cathode,and electrolyte impregnating said absorbent body.

3. An electric cell comprising a pair of open top metal cups oppositelyoriented and in mutually telescoping relation, the side walls of saidcups Ibeing spaced apart to form an annular space therebetween, a gasketbetween the edge of the inner cup and the bottom of the outer cup, saidgasket being generally U-shaped in cross section and extending incontact with the interior and exterior surfaces of the side wall of saidinner cup, said gasket permitting escape of gas under pressure from theinterior of lsaid inner cup, the major portion of the bottom of saidinner cup being dished outwardly and providing an annular shoulder onsa-id cup adjacent to said dished portion, an iii-turned flange on saidouter cup overlying said shoulder, a spacing member between said ilangeand said shoulder, a liquid-absorbent member within said annular space,means for venting gas from said annular space located beyond saidliquid-absorbent member with respect to said gasket, a third open topcup within said outer cup, a first electrode arranged in said dishedportion of said inner cup and a second electrode arranged in said thirdcup, the bottoms of said third and outer cups 'being joined together,said third cup being shallow relative to said inner and outer cups to'provide a space between said anode and said cathode, a liquid-absorbentbody between said anode and said cathode, an aqueouselectrolyteimpregnating said absorbent body, said electrolyte having solvent andsolute components, and a sheet-form barrier between said absorbent bodyand said cathode, said barrier being permeable to said solvent andsolute components, said barrier extending beyond the side wall ot saidthird cup and into contact `with said gasket.

4. An electric cell comprising a pair of open-top metal cups oppositelyoriented and in mutually telescoping rela'- t-ion, the side walls ofsaidl cups being spaced apart to form an annular space therebetween, agasket under pressure between the edge of the Iinner cup and the bottomof the outer cup, said gasket being ygenerally U-s`haped inv crosssection and extending in contact with the' interior and exteriorsurfaces of the side' wall of said inner cup, said' gasket permittingescape of gas under pressure from the interior of said inner cup, themajor portion of thev bottom of saidinner cup being dishedy outwardly'and providing an annular shoulder on said cup adjacent to` said dishedportion, an= in-turned flange on said outer cup overlying said shoulder,a spacing member between said ange and. said shoulder, aliquid-absorbent member within -said annular space and between saidspacing member and; saidl gasket, the side wall of said outer cup havingan: opening therein' at a location beyond said liquidabsorbent memberwith respect to said gasket, a' third open top cup withiny said outercup, an anode arranged in said 'dished portion of said' inner cup and acathode arranged in saifdthird' cup, the bottoms of said third" andouter' cups being' joined together, said third cup being shallowrelative toy said inner and outer cups to provide a space bet-Ween saidlanode and said cathode, a liquid- Iabsorbent body between said anodeandI said cathode, an

aqueous electrolyte impregnating said liquid-absorbent body, saidelectrolyte having solvent and solute components, and `a sheet-formbarrier between said absorbent body and said cathode, said barrier'being permeable to lsaid solvent and solute components, said barrierextending beyond the side wall of said third cup and into contact withsaid gasket.

5. An electric cell comprising a pair of open-top metal cups oppositelyoriented and in mutually telescoping relation, the side Walls of saidcups being spaced apart to form an annular space therebetween, acompliant gasket under pressure between the edge of the inner cup andthe bottom of the outer cup, sa-id gasket being generally U-shaped incross section and extending in contact with the interior and exteriorsurfaces of the side wall of `said 'inner :cu-p, said gasket permittingescape of gas under pressure from the interior of said inner cup, themajor portion of the bottom of said inner cup being fdished outwardlyand providing an annular shoulder on said cup adjacent t-o said dishedportion, an iti-turned i'lange on said `outer cup overlying saidshoulder, a substantially rigid spacing member between said flange andsaid shoulder, said spacing member permitting ready escape of gas fromsaid annular space, a liquid-absorbent member within said annular space,a third open top cup within said outer cup, an anode arranged in saiddished portion of said inner cup and a cathode arranged in said thirdcup, the lbottoms of said third and outer cups being joined together,said third cup being shallow relative to said inner and outer cups toprovide a space between said anode and said cathode, a liquid-absorbent'body between said anode and said cathode, an aqueous electrolyteimpregnating said liquid-absorbent body, said electrolyte having solventand solute components, and a sheet-form barrier between said absorbent-body and said cathode, said barrier being permeable to said solvent andsolute components, said barrier extending beyond the side wall of saidthird cup and into Contact with said gasket.

References Cited in the file of this patent UNITED STATES PATENTS

1. AN ELECTRIC CELL COMPRISING A PAIR OF OPEN TOP METAL CUPS OPPOSITELYORIENTED AND IN MUTUALLY TELESCOPING RELATION, THE SIDE WALLS OF SAIDCUPS BEING SAPCED APART TO FORM AN ANNULAR SPACE THEREBETWEEN, A GASKETUNDER PRESSURE BETWEEN THE EDGE OF THE INNER CUP AND THE BOTTOM OF THEOUTER CUP, SAID GASKET BEING ENERALLY U-SHAPED IN CROSS SECTION ANDEXTENDING IN CONTACT WITH THE INTERIOR AND EXTERIOR SURFACES OF THE SIDEWALL OF SAID INNER CUP, SAID GASKET PERMITTING ESCAPE OF GAS UNDERPRESSURE FROM THE INTERIOR OF SAID INNER CUP, THE BOTTOM PORTION OF SAIDINNER CUP PROVIDING AN ANNULAR SHOULDER, AN INTURNED FLANGE ON SAIDOUTER CUP OVERLYING SAID SHOULDER, A SPACING MEMBER BETWEEN SAID FLANGESAND SAID SHOULDER,